170 MICROSCOPIC OBJECTS. 



the purchase of a microscope, the sohd stage vertical 

 achromatic microscope described at the end of this Httle 

 book is preferable, being by far the cheapest and most 

 useful construction to be obtained for so small a sum. 



(19.) Scissors for Dissecting Minute Objects. — These 

 are far preferable to knives or lancets, for the division of 

 delicate bodies ; the best mode of constructing them is 

 shown in the annexed fio-ure. 



They are held by the handle b, which is fixed to one 

 blade, so that the fore-finger is at liberty to press upon 

 the prolongation c of the other to close them ; they are 

 always kept open and ready for cutting by a spring. 

 It is stated of Swammerdam (who has surpassed all others 

 in his dissections) by his biographer Boerhaave, "that 

 the constructing of veiy fine scissors and giving them an 

 extreme sharpness seems to have been his chief secret. 

 These he made use of to cut very minute objects, 

 because they dissected them equally ; whereas knives and 

 lancets, let them be ever so fine and sharp, are apt to 

 disorder delicate substances, as in going through them 

 they generally draw after them and displace some of the 

 filaments." 



(20.) The Microtome is a paii' of scissors somewhat 



